No. Fliiiight has extremely accurate speed, cadence, and power reporting. There's no advantage to using additional sensors. Spoke magnets or other objects installed on your spokes as part of your sensors can also interfere with Fliiiight's optical speed detection and the operation of the trainer.
If you do use a separate sensor, please note that while recording readings from your separate sensor on a bike computer or smart watch will not interfere with the trainer operation, pairing a separate sensor as the source of speed or power in your smart training app may cause commands from the app to lag and interfere with ERG tracking.
Separate Speed and Cadence sensors
Fliiiiight collects high resolution cadence and speed data, updating hundreds of times per second. There's no reason to use a separate speed or cadence sensor.
A separate powermeter is a great tool for taking the guesswork out of your outdoor training, but you won't need one while you're using your Fliiiight trainer. Fliiiight has highly accurate power reporting.
If you already have a powermeter installed on your bike, just be sure to connect to your trainer, and not your powermeter as the source of power in your training app.
Using "Power Matching" features available on some training apps is not recommended. These features can cause commands from the app to lag and interfere with ERG tracking. We recommend you use Fliiiight as your source of truth. However, you can calibrate the trainer to match another powermeter for consistency between your indoor and outdoor rides. See instructions here.